/*
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 * and open the template in the editor.
 */
package elevenHomework;

/**
 *
 * @author Administrator
 */
import java.util.LinkedHashSet;
import java.util.Scanner;
 
/**
 *
 * @author FuQianMing
 */
public class  ProblemG {
 
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        LinkedHashSet set=new LinkedHashSet();
         String str=sc.next();
         for(int i=0;i<str.length();i++)
         {
             set.add(str.charAt(i));
         }
         for(Object ss:set)
         {
             System.out.print(ss);
         }
         }
         
    }
